<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
		<style type="text/css">
			#baidu *{
				display: block;
				border: 2px solid blue;
				color: #aaaa00;
				padding: 5px;
				margin: 15px;
			}
		</style>
	</head>
	<body>
		<div id="baidu">div元素
			<ul>ul元素
				<li class="id">li000元素
					<span>span元素</span>
				</li>
				<li>li999元素
					<span>span元素</span>
				</li>
			</ul>
		</div>
		<script type="text/javascript">
			$(function(){
				$("ul").children(".id").css({"color":"red","border":"2px solid red"})
			})
		</script>
	</body>
</html>
